Troubleshooting.md

@@ -2,6 +2,8 @@
 
 Check the [format](./Base-file-format) of your numbers
 
-## My test fails randomly with the error `lines`
+## My test fails with the error `lines`
 
-If MPI-IO is enabled, be sure you don't have committed some output files (`post.mpio.bin`/ `post.mpio.txt`)
+*  If MPI-IO is enabled:
+    * Be sure that you generated your base files using **mpio2txt** with the merge `-m` option
+    * Be sure you don't have committed some output files (`post.mpio.bin`/ `post.mpio.txt`)